LKB1/PAR4 protein is asymmetrically localized in mouse oocytes and associates with meiotic spindle

The mouse secondary oocyte is polarized at the ultrastructural and molecular level, but very little is known about mechanisms involved in the establishment of this polarity. We showed that the LKB1 kinase, a mouse homologue of Caenorhabditis elegans PAR4 protein is asymmetrically localized to the animal pole of the mouse oocyte and during oocyte maturation associates with the microtubules of metaphase I and metaphase II meiotic spindles. Therefore, we suggest that LKB1/PAR4 protein, may participate in the polarization of the oocyte and in the regulation of the asymmetry of meiotic divisions during mouse oogenesis.